Boring-bar holder.



E. E. ELLIS. ao'mme B AR HOLDER. APPLICATION FILED MAY13. 19M- Patented July 4, 1916.

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m w 4 a w 5/ Y m M rL Y B EMORY E. ELLIS, OF ORANGE, MASSACHUSETTS.

BORING-BAR HOLDER.

Specification of Letters Patent.

Patented July 4,1915.

Application filed May 13, 1914. Serial No. 838,384.

To all whom it may concern Be it known that I, EMoRY E. ELLIS, a citizen of the United States, residing at Orange, county of Franklin, Commonwealth of Massachusetts, have invented certain new and useful .Improvements in Boring-Bar Holders, of which the following is a specification.

This invention relates to boring tools for metal working machines, and particularly to a boring tool holder adapted for attachment to a lathe. As is well known, the distance from the center of the lathe spindle to the top of the cross slide upon which the boring tool holder seats, varies in modern lathes. In order to adapt the holder to all lathes it is necessary that provision be made for adjusting the boring bar relative tothe cross slide of the lathe.

In my present invention I provide a head rotatable in a suitable bearing and having an eccentric tool socket in which the boring bar seats and is clamped. Rotation of the head secures an adjustment of the bar vertically relative to the cross slide to compensate for variations in the distance between the slide and spindle. After the proper adjustment has been effected, it is essential, in such a construction, that both the head and the boring bar be clamped firmly and rigidly and that the holder itself be locked absolutely rigid to the tool post of the lathe. These and other features which will appear more fully hereinafter are secured in my present invention, the construction and operation of which will be more fully disclosed in the specification which follows.

In the drawings specification I have shown as an illustrative embodiment a form of holder which has been found satisfactory in use and well adapted to the requirements of manufacture.

Throughout specification and drawings like reference numerals are employed to indicate corresponding parts, and in these drawings:

Figure 1 1s a perspective view of a boring tool holder in accordance with my invention applied to the tool post of a lathe. Fig. 2 is a perspective view of the holder removed, Fig. 3 is a front elevation of the holder broken out to show the eccentric head, and Fig. at is an end view of the holder showing in dotted lines the boring bar adjusted to a lower position.

I have indicated at 1 the cross slide of a head has an annular forming a part of this lathe of modern construction upon the top of which the integral feet 2 of the bar holder 3 rest so as to define an open-sided recess 4 of a sizeto recelve the tool post 5 of the lathe, which post is' clamped therein by inserting the tongue or latch 6 which is pivoted by a vertical pivot screw 7 to one of the feet 2 through the slot of the tool post, after the usual tool post ring has been removed. The latch swings in a horizontal plane and finds bearing on the upper face of the opposite'foot 2, both feet being flattened at'8 to receive the pressure of the latch extremities.

The bar holder 3 is formed as a solid casting having eccentrically thereof a longitudinal bore 9 providing a bearing and seat for a rotatable head or bushing 10 fitted therein and displaceable by movement longitudinally thereof. The stock of the head is taken out between its ends as indicated at 20, Fig. 3. This weakens the head and enables it to be more easily compressed. The shoulder 11 milled to assist in rotating it and acting as a stop to limit the sliding adjusting movement thereof in one direction along the bearing 9. Eccentrically thereof the head is bored longitudinally from end to end to provide a socket and bearing 12 for a boring bar 13 which has at each end broached transverse openings to receive respectively the cutter points lfl and 15 adjustably held in said openings by set screws 16.

Rotation of the eccentric head raises and lowers the boring bar relative to the cross slidesof the lathe and permits the tool to be instantly applied to any lathe, this adjustment accommodating the tool-to the varying heights between the lathe spindle and the top of the cross slide found in di'flerent lathes. Longitudinal movement of the head adjusts the boring bar accordingly to the depth of the hole to be bored.

' The seat 9 is split from end to end as indicated at 17 and the holder is provided with two set screws 19 to clamp the boring tool 13 at the desired-adjustment both with respect to its distance from the cross head and according to the depth of the hole to be boredand rendering unnecessary successive adjustments of the bar as the depth of the hole increases.

The head is split from end to end by two diagonal saw cuts 21. The cuts 21 start from a common point along the top of the I boring bar according to the depth of the head and intersect the tool socket 12 as two diverging'slits terminating near the opposite edges of the head. The purpose of the slits 21 is to secure a tightgrip on the boring bar 13 so that as the set screws 19 are tightened the slits 17 and 21 will be contracted to firmly clamp respectively the head and the bar 13. The arrangement of the slits 21 non-diametrically of the head secures a three point grip on the bar 13 which is effective to clamp the har so tightly as to make it practically integral with the head and in addition admit of a more rapid and easier tightening of the screws to contract the seats. Furthermore, the removal of the stock between the ends of the head weakens the head and makes it more flexible so that it will respond more quickly to the contracting pressure to more tightly grip the bar when theset screws 19 are tightened.

' In use the tongue 6 is inserted through the slot of the tool post and drawn toward the post until the latter fits in the recess 4 defined by the feet or extensions of the holder, whereupon the post is clamped to the holder by suitable clamping means carried by the post. The adjustment of the boring bar relative to the tool post to suit the distance between the lathe spindle and cross slide'is accomplished by rotating the eccentric head 10'. The adjustment of the hole ishad by moving the head 10 longitudinally in its bearing. When the desired adjustment has been found the set screws 19 are tightened to contract the bearing 9 and tool socket 12 and clamp the head and boring bar in adjusted position. The head being slit as described secures a .very tight grip on the bar, while it, itself, is firmly clamped in its bearing.

Various modifications in the construction and form of my invention coming within its scope and spirit may obviously be resorted to if found within the limits of the appended claims. I

What I therefore claim and desire to secure by Letters Patent is:

1. A boring bar holder comprising a bear ing, a head adjustable therein and having a split tool socket extending from end to end thereof, said head having the stock between its ends and below said split socket removed, leaving connected end portions spaced by said. cut-out and fitting said hearing, and means for holding. the adjustment of said head in the bearing.

2. A boring bar holder comprising a tool post attachment having a bearing, a head adjustable therein and having an eccentrically disposed tool socket, said head having slits extending from said tool, socket in divergent planes and extending from end to end of the head, and having the stock between its ends removed to increase its flexibility, means for clampingsaidhead in said bearing, and means for rigidly locking said attachment to a tool post.

3. In combination with the cross slide of a lathe, a tool post thereon, a boring holder having a bearing, a head adjustable therein, said head having non-diametric slits extending'from end to end thereof and having a tool socket therein intersected by said slots, the stock of said head between its ends and below the ends of said slots being removed to increase the flexibility of the head without destroying the eifective grip of the tool socket, means for holding the ad justment of said head in said bearing, and means for rigidly locking said holder to said tool post.

4. A boring bar holder comprising-a hearing, a head longitudinally and rotatably adjustable therein, and terminating beyond one end of said bearing in an enlarged portion, disposed to abut said bearing and stop the movement of said head in one direction, said head having a diagonally split tool socket and having the stock betweenv said enlarged portion and its opposite end and below said tool socket removed'leaving connected portions spaced by said cut-out and fitting said hearing, and means for contracting said split to'ol socket.

In testimony whereof I afiix my signature in presence of two witnesses. v

EMORY E. ELLIS,

.Witnessesr FRANK T. WATERS, RUBY I. LEE. 

